Wave Optics — Physics STD 12 Science — Question

Identify the correct options:

A metal block is exposed to beams of X-ray of different wavelength. X-rays of which wavelength penetrate most

(a) 2 Å

(b) 4 Å

(c) 6 Å

(d) 8 Å

How is galvanometer converted into a voltmeter?

In Millikan's experiment for the determination of the charge on the electron, the reason for using the oil is

(a) It is a lubricant	(b) Its density is higher
(c) It vapourises easily	(d) It does not vapourise

In an area of constant magnetic field, a charged particle enters in a direction parallel to the direction of magnetic field with its velocity. The speed of particle is:

A generator has an e.m.f. of 440 volt and internal resistance of 400 ohm. Its terminals are connected to a load of 4000 ohm. The voltage across the load is:

An e.m.f. of 12 volts is induced in a given coil when the current in it changes at the rate of 48 amperes per minute. The self inductance of the coil is

(a) 0.25 henry

(b) 15 henry

(c) 1.5 henry

(d) 9.6 henry

Two capacitors each having capacitance C and breakdown voltage V are joined in series. The capacitance and the breakdown voltage of the combination will be:

In a nuclear reactor, the fuel is consumed at the rate of 1 mg/s. The power generated in kilowatt is

(a) 9

(b) 9

(c) 9

(d) 9

Smaller pieces of heavy stones and metals which on entering earth's atmosphere burns out are

(a) Comets

(b) Meteorites

(c) Asteroids

(d) All of these